isbogrel and ozagrel

Effects of thromboxane A2 (TXA2) synthase inhibitors (CV-4151 and ozagrel) on cerebral thrombosis and cerebral damage were examined in a rat middle cerebral artery (MCA) thrombosis model and their potencies were compared with the conventional antithrombotic agents, aspirin and ticlopidine. CV-4151 significantly inhibited photochemically induced MCA thrombosis by oral (1 and 10 mg/kg) and intravenous (1 mg/kg) administration. Ozagrel (10 mg/kg, p.o.) also inhibited it. The potency of CV-4151 was about 10 times stronger than that of ozagrel, being comparable with the inhibition of blood TXA2 generation. Aspirin (100 mg/kg, p.o.) and ticlopidine (300 mg/kg, p.o.) showed an inhibitory tendency on MCA thrombosis. Twenty-four h after photochemical stimulation, cerebral edema and cerebral infarction were observed, and the lactate content in the brain increased. CV-4151 and ozagrel prevented this edema, and the antiedema effects of the drugs were correlated with the antithrombotic effect on thrombotic MCA occlusion. CV-4151 (10 mg/kg, p.o.), furthermore, significantly reduced the infarct size and inhibited the increase in lactate content. These results indicate that TXA2 synthase inhibitors inhibit cerebral damage by inhibition of MCA occlusion with thrombosis, probably resulting from the inhibition of TXA2 generation, and their effects are superior to those of aspirin and ticlopidine. TXA2 might play an important role in cerebral damage in the MCA thrombosis model. CV-4151 might be a useful drug for the treatment of cerebral thrombosis and for the prevention of cerebral infarction.

Topics: Animals; Aspirin; Brain Chemistry; Brain Edema; Cerebral Arteries; Cerebral Infarction; Drug Evaluation, Preclinical; Fatty Acids, Monounsaturated; Fibrinolytic Agents; Guinea Pigs; Intracranial Embolism and Thrombosis; Lactates; Lactic Acid; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Male; Methacrylates; Photochemistry; Potassium; Pyridines; Rabbits; Rats; Rats, Sprague-Dawley; Rose Bengal; Sodium; Thromboxane A2; Ticlopidine

Synthesis and pharmacological evaluation of novel indazole derivatives are described. These compounds were found to exhibit both thromboxane A2 (TXA2) synthetase-inhibitory and bronchodilatory activities. This observation supports the idea that the partial structure of the 3-pyridyl and phenyl groups with a methylene insertion is an important component for well-balanced activities.

Topics: Administration, Oral; Aminophylline; Animals; Benzofurans; Bronchodilator Agents; Fatty Acids, Monounsaturated; Guinea Pigs; Histamine Antagonists; In Vitro Techniques; Indazoles; Male; Methacrylates; Pentanoic Acids; Pyridines; Rats; Rats, Sprague-Dawley; Structure-Activity Relationship; Thromboxane-A Synthase; Trachea

The antiplatelet and antithrombotic effects of CV-4151 (isbogrel), a potent selective thromboxane A2 (TXA2) synthase inhibitor, were compared with those of ozagrel (OKY-046), aspirin, and ticlopidine in rats. Two hours after oral administration, CV-4151, ozagrel and aspirin inhibited blood TXA2 generation with ID50 values of 0.04, 0.3 and 6.4 mg/kg, respectively. These values were similar to the oral ID50 values of CV-4151 (0.06 mg/kg), ozagrel (0.92 mg/kg) and aspirin (7.0 mg/kg) for arachidonic acid (AA)-induced platelet aggregation ex vivo. Two hours after p.o. administration, CV-4151 and ozagrel inhibited femoral vein platelet-rich thrombosis caused by endothelial injury with ID50 values of 2.46 and 13.7 mg/kg, respectively. However, aspirin (100 mg/kg, p.o.) only slightly inhibited the thrombosis. Ticlopidine (300 mg/kg, p.o.) slightly but significantly inhibited AA-induced and ADP-induced platelet aggregation, however, it potently inhibited the thrombosis. CV-4151 and ozagrel given by i.v. injection showed therapeutic effects on the thrombosis with ED50 values of 0.026 and 0.066 mg/kg, respectively. These values were similar to the i.v. ED50 values of CV-4151 (0.0056 mg/kg) and ozagrel (0.042 mg/kg) for blood TXA2 generation. However, aspirin (30 mg/kg, i.v.) only moderately reduced the thrombosis. CV-4151 (> 0.3 mg/kg, p.o.), ozagrel (> 3 mg/kg, p.o.) and ticlopidine (300 mg/kg, p.o.) all significantly prolonged tail bleeding time. Aspirin (100 mg/kg, p.o.) tended to prolong the bleeding time. The antiplatelet and antithrombotic effects of CV-4151 are more potent than those of ozagrel, aspirin and ticlopidine in rats. CV-4151 may therefore be a useful drug for the treatment of thrombotic diseases.

Topics: Animals; Aspirin; Bleeding Time; Endothelium, Vascular; Fatty Acids, Monounsaturated; Femoral Vein; Male; Methacrylates; Platelet Aggregation; Pyridines; Rats; Rats, Sprague-Dawley; Thrombosis; Thromboxane-A Synthase; Thromboxanes; Ticlopidine

We established an experimental model of late asthmatic response (LAR) using conscious guinea pigs actively sensitized by antigen aerosol inhalation. In actively sensitized guinea pigs, antigen challenge by aerosol inhalation caused an immediate increase in specific airway resistance (SRaw) (immediate airway response; IAR) followed by a LAR which occurred 4 to 8 hr after antigen challenge. SRaw in the challenged animals was still increased 23 hr after antigen challenge. Examination of bronchoalveolar lavage (BAL) fluid and histology of the lungs revealed increases in eosinophils and neutrophils during LAR. The beta-2 agonist salbutamol inhibited only IAR and not LAR. Dexamethasone inhibited LAR but not IAR. A low dose of theophylline had little effect on both IAR and LAR. A novel thromboxane A2 (TXA2) receptor antagonist, AA-2414, orally administered before antigen challenge dose-dependently inhibited both IAR and LAR, and oral administration of AA-2414 after the IAR inhibited LAR. Also, thromboxane synthetase inhibitors, CV-4151 and OKY-046, reduced both IAR and LAR. Salbutamol significantly reduced the increase in neutrophils in BAL fluid, and dexamethasone significantly reduced the increase in eosinophils and neutrophils in BAL fluid. Theophylline also reduced the increase in eosinophils in BAL fluid. However, AA-2414 did not inhibit the accumulation of these inflammatory cells in BAL fluid or the airway tissues. These results suggest that asthmatic responses in guinea pigs are similar to those in asthmatic subjects and that TXA2 plays an important role in both IAR and LAR but not in inflammatory cell infiltration in this model of allergic asthma.

Topics: Acetylcholine; Airway Resistance; Animals; Antibodies; Asthma; Benzoquinones; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Fatty Acids, Monounsaturated; Guinea Pigs; Heptanoic Acids; Leukocytes; Male; Methacrylates; Ovalbumin; Pyridines; Theophylline; Thromboxane A2

Topics: Arterial Occlusive Diseases; Aspirin; Chronic Disease; Epoprostenol; Fatty Acids, Monounsaturated; Humans; Methacrylates; Polydeoxyribonucleotides; Pyridines; Thromboxane A2; Thromboxane-A Synthase